Foamable resin molding with foamable resin injected into a mold can reduce the weight and materials of a molded article because of the use of the foamable resin. Unfortunately, the foamable resin molding may reduce the strength of the molded article, which is a problem in practical use.
In order to address this problem, Patent Literature 1 describes a molding method in which a mold surface is cooled to defoam the surface of a molded article, thereby suppressing a reduction in strength.
In FIGS. 10(a) and 10(b), a cavity 42 formed by a stationary mold 31 and a movable mold 32 is filled with foamable resin R. The outer edge of the stationary mold 31 includes a groove 31a that forms an attaching portion Xb.
In FIG. 10(c), the movable mold 32 undergoes a core-back operation in the direction of an arrow, that is a direction along which the volume of the cavity 42 increases. Reference character Ra denotes foam cells and reference character Xc denotes a skin layer having a small porosity. The attaching portion Xb is formed continuously to the body of a molded article.
In the step of producing the molded article, the foamable resin R disposed in the groove 31a of the stationary mold 31 has a relatively small volume and thus is quickly cooled and solidified on a surface of the stationary mold 31 around room temperature, suppressing a reduction in pressure. Thus, the attaching portion Xb is formed with suppressed growth of the foam cells Ra.